报错信息：
java.lang.IllegalStateException: failed to load plugin - Plugin information:
Name: analysis-ik
Description: IK Analyzer for Elasticsearch
Version: 5.6.8
Native Controller: false
* Classname: org.elasticsearch.plugin.analysis.ik.AnalysisIkPlugin due to jar hell
at org.elasticsearch.plugins.PluginsService.loadBundles(PluginsService.java:380) ~[elasticsearch-5.6.8.jar:5.6.8]
at org.elasticsearch.plugins.PluginsService.(PluginsService.java:141) ~[elasticsearch-5.6.8.jar:5.6.8]
at org.elasticsearch.node.Node.(Node.java:313) ~[elasticsearch-5.6.8.jar:5.6.8]
at org.elasticsearch.node.Node.(Node.java:245) ~[elasticsearch-5.6.8.jar:5.6.8]
at org.elasticsearch.bootstrap.Bootstrap$5.(Bootstrap.java:233) ~[elasticsearch-5.6.8.jar:5.6.8]
at org.elasticsearch.bootstrap.Bootstrap.setup(Bootstrap.java:233) ~[elasticsearch-5.6.8.jar:5.6.8]
at org.elasticsearch.bootstrap.Bootstrap.init(Bootstrap.java:342) [elasticsearch-5.6.8.jar:5.6.8]
at org.elasticsearch.bootstrap.Elasticsearch.init(Elasticsearch.java:132) [elasticsearch-5.6.8.jar:5.6.8]
at org.elasticsearch.bootstrap.Elasticsearch.execute(Elasticsearch.java:123) [elasticsearch-5.6.8.jar:5.6.8]
at org.elasticsearch.cli.EnvironmentAwareCommand.execute(EnvironmentAwareCommand.java:70) [elasticsearch-5.6.8.jar:5.6.8]
at org.elasticsearch.cli.Command.mainWithoutErrorHandling(Command.java:134) [elasticsearch-5.6.8.jar:5.6.8]
at org.elasticsearch.cli.Command.main(Command.java:90) [elasticsearch-5.6.8.jar:5.6.8]
at org.elasticsearch.bootstrap.Elasticsearch.main(Elasticsearch.java:91) [elasticsearch-5.6.8.jar:5.6.8]
at org.elasticsearch.bootstrap.Elasticsearch.main(Elasticsearch.java:84) [elasticsearch-5.6.8.jar:5.6.8]
Caused by: java.util.zip.ZipException: error in opening zip file
at java.util.zip.ZipFile.open(Native Method) ~[?:1.8.0_162]
at java.util.zip.ZipFile.(ZipFile.java:225) ~[?:1.8.0_162]
at java.util.zip.ZipFile.(ZipFile.java:155) ~[?:1.8.0_162]
at java.util.jar.JarFile.(JarFile.java:166) ~[?:1.8.0_162]
at java.util.jar.JarFile.(JarFile.java:103) ~[?:1.8.0_162]
at org.elasticsearch.bootstrap.JarHell.checkJarHell(JarHell.java:180) ~[elasticsearch-5.6.8.jar:5.6.8]
at org.elasticsearch.plugins.PluginsService.loadBundles(PluginsService.java:378) ~[elasticsearch-5.6.8.jar:5.6.8]
... 13 more
首先进入ik插件目录执行ls -al查看所有文件信息包括隐藏文件，如果出现以下这种.格式的文件，就执行rm -rf .*删除掉所有._开头的文件：
._commons-codec-1.9.jar commons-codec-1.9.jar ._commons-logging-1.2.jar commons-logging-1.2.jar config ._config ._elasticsearch-analysis-ik-5.6.8.jar elasticsearch-analysis-ik-5.6.8.jar ._httpclient-4.5.2.jar httpclient-4.5.2.jar ._httpcore-4.4.4.jar httpcore-4.4.4.jar ._plugin-descriptor.properties plugin-descriptor.properties
注意config目录中是否也存在._开头的文件
cd config/
ls -al
._extra_main.dic extra_main.dic ._extra_single_word.dic extra_single_word.dic ._extra_single_word_full.dic extra_single_word_full.dic ._extra_single_word_low_freq.dic -extra_single_word_low_freq.dic ._extra_stopword.dic extra_stopword.dic ._IKAnalyzer.cfg.xml IKAnalyzer.cfg.xml ._main.dic main.dic ._preposition.dic preposition.dic ._quantifier.dic quantifier.dic ._stopword.dic stopword.dic ._suffix.dic suffix.dic ._surname.dic surname.dic
rm -rf ._*
删除完重启启动es即可。
